Adjust log message

go/topology/volume_layout.go

@@ -42,7 +42,7 @@ func (vl *VolumeLayout) RegisterVolume(v *storage.VolumeInfo, dn *DataNode) {
 		vl.vid2location[v.Id] = NewVolumeLocationList()
 	}
 	vl.vid2location[v.Id].Set(dn)
-	glog.V(4).Infoln("volume", v.Id, "added to dn", dn, "len", vl.vid2location[v.Id].Length(), "copy", v.ReplicaPlacement.GetCopyCount())
+	glog.V(4).Infoln("volume", v.Id, "added to dn", dn.Id(), "len", vl.vid2location[v.Id].Length(), "copy", v.ReplicaPlacement.GetCopyCount())
 	if vl.vid2location[v.Id].Length() == vl.rp.GetCopyCount() && vl.isWritable(v) {
 		vl.AddToWritable(v.Id)
 	} else {